1. Technical Field
Aspects of the present invention relate to detection and documentation of tailgating and speeding violations.
2. Description of Related Art
United States patent application publication US2011/0234749 by the same inventor, discloses a system for detecting and recording real-time law violations. A law enforcement motor vehicle is equipped with an array of cameras providing multiple image streams over a substantially 360° field of view around the law enforcement motor vehicle.
Tailgating is an unsafe practice performed by a driver of a trailing vehicle following a lead vehicle too closely on a road. The German Highway code defines the driving offense of tailgating as traveling too closely to the vehicle in front. The German Highway Code (Straßenverkehrsordnung, StVO) does not specify a minimum distance to a lead vehicle. The code section 4 states that a driver must leave enough distance to the vehicle in front in order to be able to stop if the lead vehicle brakes suddenly. For heavy goods vehicles on the other hand, the German Highway Code specifies a minimum distance of at least 50 metres (see § 4(3) StVO). German case law requires that a car traveling on a dual carriageway or other high-speed road should maintain a minimum distance to the lead vehicle specified by the speed of travel during 1.5 seconds. The minimum distance may be 250-300 metres. Momentarily traveling less than the minimum distance to the lead vehicle in front should not result in an infraction. In addition, the prosecution is expected to prove that the act of tailgating caused a danger to other road users. Proving the act of tailgating caused a danger to other road users may be essentially a question of judgment and open to dispute.
The United Kingdom highway code defines driving too closely to lead vehicle in terms of a stopping distance which includes a thinking distance added to a braking distance. The thinking distance depends on the attention of the driver whilst the braking distance takes into consideration the road surface, the type of weather conditions and the condition of the vehicle. A vehicle traveling at 64 kilometres per hour (kph) has a stopping distance of 36 meters which includes 12 meters of thinking distance and 24 meters of braking distance. In contrast, a vehicle traveling at 112 KPH has a stopping distance of 96 meters which includes 21 meters of thinking distance and 75 meters of braking distance.
Various systems and methods for detecting tailgating violations have been proposed. The abstract of “A Mobile Tailgating Detection System for Law Enforcement Surveillance.” (Zellmer, Tyler J., et al., ASME 2014 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2014) notes that “Tailgating is difficult to detect and document using visual methods and law enforcement agencies must depend on trained officers, whose abilities may be limited”. (emphasis added) The proposed tailgating detection system is mounted on a law enforcement patrol host vehicle which continuously monitors both passenger and commercial vehicles, as the host vehicle travels along the roadway. A rotating laser range-finding sensor feeds information to a microprocessor that continuously searches for the occurrence of tailgating. A weighting algorithm determines when a tailgating event has definitively occurred to reduce system sensitivity. If an event is detected, the officer is notified with audio and visual cues. A time stamped record including all relevant system information for later use in legal prosecution is also produced.
Laser radar or LIDAR used to detect speeding violations has been used also for detecting tailgating. However, LIDAR systems detect tailgating only when directed in line with the road on which vehicles are traveling.
Thus, there is a need for and it would advantageous to have a system a method for visually determining that a trailing vehicle is tailgating a lead vehicle when viewed from various directions.